Considering our characters wouldn’t be particularly dialogue heavy I wanted our character to convey a lot of their emotions through their eyes, as a result, I thought I would be an interesting addition, if the Iris’s were able to dilate.
And the way I went about doing this was through the use of blend shapes.
I started by duplicating the original Iris mesh and extruded its central vertices inwards as shown above.
I then selected the modified duplicate mesh followed by the original mesh (the mesh I wanted the blend deformer to be applied to) and under the modelling menu, went to deform and Blend Shape.
As seen above in the attribute editor, the blend deformer has now been applied to the Iris mesh.
I found the following video particularly helpful to achieve the end result, I thought it was very easy to understand and straight forward to follow: